With increasing development of communication technologies, a 3G data card could be externally connected to a mobile electronic device such as a notebook computer, a personal digital assistant (PDA) or a media information device (MID). Therefore, such a mobile electronic device is also referred as a 3G mobile communication device.
For example, when a 3G data card is connected to a notebook computer, the notebook computer will possess the functions of wireless network connection and wireless communication. In other words, wherever and whenever the user is, the notebook computer could be connected to the Internet or used as a communicating device as long as the notebook computer is in communication with a base station of a mobile network system.
FIG. 1 is a schematic functional block diagram illustrating a notebook computer that is connected to a 3G data card according to the prior art. As shown in FIG. 1, the notebook computer 100 comprises a control circuit unit 120. The control circuit unit 120 comprises a central processing unit (CPU) 102, a north bridge chip 104 and a south bridge chip 106. The notebook computer 100 further comprises a peripheral component interconnect mini card (or PCI-Express mini card) interface. Via a USB interface of the PCI-Express mini card interface, the 3G data card 150 and the control circuit unit 120 communicate with each other to exchange data in order to implement the functions of wireless network connection and wireless communication.
For example, for making phone calls over the internet by the notebook computer 100, the notebook computer 100 needs to be in communication with a base station of a mobile network system through the connection between the control circuit unit 120 and the 3G data card 150.
Similarly, the personal digital assistant (PDA) includes a control circuit unit, for example an ARM9 processor or an ARM11 processor. Via the USB interface, the ARM9 processor and a 3G data card communicate with each other to exchange data, so that the PDA possesses the wireless network connection and wireless communication. Similarly, the media information device (MID) also has a control circuit unit to be connected with a 3G data card.
Please refer to FIG. 1 again. As known, the notebook computer 100 has several power-saving modes (e.g. S3 or S5 power-saving mode). S0 is the normal working mode of the notebook computer 100. According to the time needed to bring the notebook computer 100 back to the normal working mode S0, the notebook computer 100 enters different power-saving modes. For example, the notebook computer 100 is switched from the normal working mode S0 to the power-saving mode S3 if the notebook computer 100 has not been used for a relative longer time. Whereas, the notebook computer 100 is switched from the normal working mode S0 to the power-saving mode S5 if the notebook computer 100 has not been used for a relative shorter time.
In a case that the user intends to communicate with the base station through the 3G data card 150 when the notebook computer 100 is in a power-saving mode, the user could easily operate the notebook computer 100 to have the notebook computer 100 enter the normal working mode S0. As such, the user could make phone calls or link to the Internet by using the notebook computer 100.
On the other hand, in a case that an external phone call is being received by the 3G data card 150 when the notebook computer 100 is at a power-saving mode, the 3G data card 150 has no mechanism to wake up the notebook computer 100. Under this circumstance, the external phone call fails to be received by the notebook computer 100. In other words, for effectively receiving the external phone call, the notebook computer 100 that is connected to the 3G data card 150 should be continuously maintained at the normal working mode S0.
Since the notebook computer 100 that is connected to the 3G data card 150 fails to enter the power-saving mode, the power consumption of the notebook computer 100 is considerable and the built-in battery fails to provide electricity for a long time. Similarly, the above drawbacks occur when the personal digital assistant (PDA) or the media information device (MID) is connected to a 3G data card.